There are two flavors of CALs -- User CALs, which allow a unique user to connect any device they own, and the Device CALs, which associate a per device license fee. Previously Microsoft had set these two licensing options to the same price.

That was great news for enterprise users, as one of the hottest trends right now in IT is the bring-your-own-device (BYOD) craze. BYOD means that one user may not only connect from both a work machine (say a work laptop), but also personal machines they own (say their personal tablet and laptop). If a business was to buy a Device CAL license, it'd have to buy three licenses for those devices, but with the User CAL, the employee had the flexibility to use any of those devices, while the employer was on the hook for only a single license fee.

But the deal is about to get a little less sweet, as Microsoft has announced that it will be bumping the price of its various User CALs by 15 percent. The price change will take affect Dec. 1. However, large customers that have Enterprise Agreements, Enterprise Subscription, Open Value Subscription, and Open Value Perpetual will be able to hang on to their current pricing until the end of their contract.

Ultimately this seems like a smart move for Microsoft. After all, a 15 percent premium User CAL is still the cheaper option for enterprise customers, if the average user connects with 2 or more devices. But the move could also backfire, forcing some smaller clients to free, open source alternatives. However, making such a switch can be costly and the end result may be inferior software, in some cases.

For those reasons it seems unlikely that Microsoft will see mass defections, even if it may be offering up an irritating change to its business clients.

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